Flexible leaf springs for kickers and clamps for log stackers

ABSTRACT

A material handling vehicle including a load handling head mounted upon the end of a boom, said load handling head including a load carrying platform, a pair of clamping arms and a pair of kicking or platform sweeping arms. The clamping arms, used for retaining the load in place upon the platform, are of a flexible spring material enabling them to equalize pressure on and conform to the irregular loads without damage to the clamps. The pair of kicker arms, likewise of a spring material, are used for removing the loads from the platform and are flexible so that they may exert pressure against unevenly shaped loads without material damage to the &#39;&#39;&#39;&#39;kickers&#39;&#39;&#39;&#39; or load removed.

[ 1 I June 13, 1972 FLEXIBLE LEAF SPRINGS FOR KICKERS AND CLAMPS FOR LOGSTACKERS Inventors: Darrel L. Bryan; Larry D. Maisch, both of OverlandPark, Kans.

Pacific Car and Foundry Company, Bellevue, Wash.

Filed: June 26, 1970 Appl. No.: 50,032

Assignee:

References Cited UNITED STATES PATENTS Magnuson ..214/778 X Wagner..214/510 2,873,874 2/ 1959 Best et a1. ..214/654 2,786,591 3/1957Neumeister. 2,684,165 7/1954 Hill Primary Examiner-Robert G. SheridanAssistant Examiner-John Mannix Attorney-Seed, Berry & Dowrey ABSTRACT Amaterial handling vehicle including a load handling head mounted uponthe end of a boom, said load handling head including a load carryingplatform, a pair of clamping arms and a pair of kicking or platformsweeping arms. The clamping arms, used for retaining the load in placeupon the platform, are of a flexible spring material enabling them toequalize pressure on and conform to the irregular loads without damageto the clamps. The pair of kicker arms, likewise of a spring material,are used for removing the loads from the platform and are flexible sothat they may exert pressure against unevenly shaped loads withoutmaterial damage to the kickers" or load removed.

4 Claims, 3 Drawing Figures PATENTEnJun 13 m2 3. 669.293

sum 2 er 2 FIG=3 4 LARRY D. MAISOH INVENTORS DARREL L. BRYAN ATTORNEYSFLEXIBLE LEAF SPRINGS FOR KICKERS AND CLAMPS FOR LOG STACKERS BACKGROUNDOF THE INVENTION This invention relates to a material handling vehicleintended primarily for the hauling and stacking of logs andparticularly, a vehicle of the type disclosed in US. Pat. No. 3,352,442,granted Nov. 14, 1967.

Briefly, the vehicle disclosed in the above noted patent is of the typein which the load is carried on a boom structure including parallelmotion arms enabling a platform upon which the load is carried to beeither tilted or maintained at a given angularity within the limitsdefined by the structure. The above noted vehicle further includes apair of clamping arms supported for swinging movement about a horizontalaxis for facilitating loading of the platform and keeping the load uponthe platform and another set of arms mounted for swinging movement abouta horizontal axis designed to permit a sweeper function to facilitateoff-loading of the platform.

The invention proposes to provide a vehicle of this character engineeredso that it will handle unusually heavy loads of logs which by their verynature have varying dimensions, each log being tapered. Each loadcomprises a plurality of logs which are not uniformly stacked.

It is an object of the present invention to provide a load handlingvehicle wherein the clamping arms used for gripping and holding the loadupon a platform as well as the arms used for sweeping the platform toassist in unloading are of a flexible nature enabling them to bend ordistort and adjust to variable dimensions of the load without breakageor damage to either the load or the vehicle itself.

Another object of the present invention is to provide a load handlingvehicle wherein a pair of clamping arms used for gripping the load areindividually controlled allowing adjustment to loads of varyingdimensions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewillustrating the material handling vehicle constructed in accordancewith the preferred embodiment of the present invention, the materialhandling head and boom structure shown in two of its possible positionsrepresented in one instance by full lines .and the other by phantomlines;

FIG. 2 is a top plan view of the forward end of the vehicle depicted inFIG. 1; and

FIG. 3 is a perspective view of the load handling head of that vehicledepicted in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS The illustrative vehicle isconstructed in a conventional manner having an engine and drive linemounted upon a longitudinal main frame 2. A pair of wheels 4 at one endof the main frame serve as traction devices and a pivotally mounted pairof closely adjacent wheels 6 at the other end of the frame perform asteering function. The steerable end will be referred to as the rearend.

At the rear end of the vehicle there is a cab 8 as well as the drivingengine and necessary steering mechanism. Mounted to the framework 2directly in front of the cab 8 is a pair of generally verticallyoriented upright beams 10, one mounted on each side of the vehicle tothe frame 2. For horizontal stability, each of the upright beams 10 havean angular, forwardly directed support rod 12 which extends from theupper portion of each beam 10 to the framework 2. Pivotally mounted at aposition between the two uprights l0is a boom 14 which extends forwardlyto terminate in the load-handling head 16. Pivotally mounted at oneendto the lower portion of the upright 10, but above the framework 2, isa forwardly extending control rod 15 which has the other end pivotallymounted to a walking beam 18 which extends in a generally upwarddirection and has pivotally mounted at the upper portion, the loadinghead 16. As can be seen in FIG. 1, the arrangement of structuralelements hereinabove described, allows the boom 14 to be raised by apair of generally vertically disposed cylinders 22 mounted between theframe 2 and the boom 14, while keeping the loading head 16 in uniformThe loading head, as best seen in FIG. 3, comprises a pair of generallyvertically upright main support members 30, having outwardly curvedupper portions, pivotally mounted upon the outwardmost or forwardmostend of the boom 14. Rigidly mounted to the lower portion of the uprights30 is a spanning beam 32 (FIG. 3) which has mounted to the forwardsurface and at opposite ends thereof, a pair of forwardly extendingbrackets 34 which have respectively mounted therein a pair of forwardlyextending tapered forks 36. The connection between the forks 36 and thebracket 34 is such that the arms are capable of pivoting upwardly only.Mounted to the upper portion of the beam 32 and secured to the uprights30 is a spanning plate 38 which serves the function of both increasingthe structural integrity of the head as well as providing a solid rearsurface at the point where the platform joins the uprights 30.

Pivoted to the upper and outwardly extending end of the curved uprights30 are a pair of downwardly depending support brackets 40 which arerigidly attached to a tubular structure Tube 42 extends laterallyoutwardly of the uprights 30 as well as spanning the distancetherebetween.

Rigidly mounted to the outboard ends of the tube 42 for rotationtherewith are a pair of brackets 44 which serve as mounting means forkicker bars 46. The kicker bars 46 are made out of a flexible materialsuch as a plurality of leaf springs as shown such that if the materialcarried upon the material-handling head 16 is of irregular dimensions,one of the bars 46 can be flexed to accommodate the irregular shapewithout structural damage.

Rigidly mounted to tube 42 intermediate the curved uprights 30 is anupstanding bracket 48 to which is mounted a hydraulic cylinder 50 whichextends rearwardly and is secured at its rearward end to a bracket 52mounted to a plate 54 (FIG. 2) which extends between the curved uprights30 at their rearward portion. The operation of the kicker bars 46 isinstituted by activating the cylinder 50 which will move the bracket 48,turning the tube 42 and its mounting brackets 40, causing brackets 44and attached flexible kicker bars 46 to pivot about the axis of theupper and outwardly extending ends of the curved uprights 30. Themovement of the bars 46 forces anything located upon the platform ofithe forward end thereof.

Mounted upon the outside of the upper portion of the curved uprights 30are a pair of platforms 56 which support one end of a pair ofindependently activated double-acting air motors or hydraulic rams 58which are attached at their other end to upstanding brackets 60 rigidlyattached to a pair of clamping arms. The clamping arms are pivotallymounted between the outermost end of the curved uprights 30 and brackets62 which are mounted upon tube 42 outwardly of the curved uprights 30but inboard of the kicker bar mounting brackets 44. The clamping armsthemselves comprise two integrated elements, the first of which is arigid metallic arm member 64 pivotally mounted as noted above, thesecond of which is a downwardly extending spring steel arm 66 rigidlyconnected to arm 64. The use of the downwardly extending spring steelarms 66 enables the clamping arms to firmly grasp material of unevendimensions without undue stress and breakage occuring to the structuralelements. The fact that the air motors or hydraulic rams 58 areindependently operated allows greater securing pressure to be used onone arm than on the other.

In operation, the loading head described in detail above, operates in astandard fashion whereat the air motors or hydraulic cylinders 58 areactivated to lift the gripper arms upwardly leaving an open space at theloading head. The entire vehicle is driven forwardly forcing forks 36under the material intended to be lifted, the material being forced backagainst the uprights 30. Once the load is so located, the clamping armsare again activated and pivoted downwardly to hold the material in placeon the platform, When it is desired to remove the material, the entireplatform is tilted forwardly and the kicker arms are activated sweepingthe platform of all material carried thereupon.

It is to be understood that although the operation of the clamping anns66 and the kickers 46 may well be independent, it is well within thescope of this invention to provide valving such that the kickers 46 maynot be operated unless the clamping arms are simultaneously raised. Thevalving required is considered to be well within the scope of oneskilled in the art and so is not shown or described.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination with a vehicle main frame; a mounting beam secured tothe frame, a boom pivoted at its inner end to the upper end of the beamfor vertical swing movement about a transverse horizontal axis, a loadhandling head pivoted at its lower end to the outer end of the boom forvertical tilting movements, an upright walking beam fulcrumed to theboom intermediate the ends thereof for rocker movement about an axisparallel to the axis of swing of the boom, a fixed length link pivotallysecured at one end to the lower end of the walking beam and at itsopposite end pivotally secured to a point upon the mounting beam, anextendible link pivotally secured the load handling head, means forraising and lowering said boom, said load handling head comprisingforwardly extending load handling forks terminating in a rigid verticalmember at the rearwardmost end of said forks and powered forwardlyextending load clamping means and means pivotally securing the latter toand forwardly of the upper portion of the vertical to the upper end ofthe walking beam and to the upper end of member, said load clampingmeans comprising generally downwardly extending rearwardly curvedflexible load contacting laterally spaced arms each fabricated of aplurality of leaf spring elements of different lengths such that thearms are increasingly more flexible as the distance from the pivot meansbecomes greater whereby the free ends of the spring elements extendsubstantially to the forks in clamping position so as to clamp the loadbetween the spring elements and the vertical member, said springelements independently flexing to accommodate irregular objects.

2. A combination as in claim 1 wherein each of the arms is independentlyoperated.

3. A combination as in claim 1 wherein there is further included apowered pivotable flexible kicker means for sweeping the load from theforks.

4. A combination as in claim 3 wherein the clamping means simultaneouslyreleases upon operation of the kicking means.

* i l l

1. In combination with a vehicle main frame; a mounting beam secured tothe frame, a boom pivoted at its inner end to the upper end of the beamfor vertical swing movement about a transverse horizontal axis, a loadhandling head pivoted at its lower end to the outer end of the boom forvertical tilting movements, an upright walking beam fulcrumed to theboom intermediate the ends thereof for rocker movement about an axisparallel to the axis of swing of the boom, a fixed length link pivotallysecured at one end to the lower end of the walking beam and at itsopposite end pivotally secured to a point upon the mounting beam, anextendible link pivotally secured to the upper end of the walking beamand to the upper end of the load handling head, means for raising andlowering said boom, said load handling head comprising forwardlyextending load handling forks terminating in a rigid vertical member atthe rearwardmost end of said forks and powered forwardly extending loadclamping means and means pivotally securing the latter to and forwardlyof the upper portion of the vertical member, said load clamping meanscomprising generally downwardly extending rearwardly curved flexibleload contacting laterally spaced arms each fabricated of a plurality ofleaf spring elements of different lengths such that the arms areincreasingly more flexible as the distance from the pivot means becomesgreater whereby the free ends of the spring elements extendsubstantially to the forks in clamping position so as to clamp the loadbetween the spring elements and the vertical member, said springelements independently flexing to accommodate irregular objects.
 2. Acombination as in claim 1 wherein each of the arms is independentlyoperated.
 3. A combination as in claim 1 wherein there is furtherincluded a powered pivotable flexible kicker means for sweeping the loadfrom the forks.
 4. A combination as in claim 3 wherein tHe clampingmeans simultaneously releases upon operation of the kicking means.